_messages = array(); $valueString = (string) $value; if (!ctype_xdigit($valueString)) { $this->_messages[] = "'$valueString' has not only hexadecimal digit characters"; return false; } return true; } /** * Defined by Zend_Validate_Interface * * Returns array of validation failure messages * * @return array */ public function getMessages() { return $this->_messages; } }